Shoeless feet hit the ground differently, a new study says

Going barefoot isn't just for strolling on the beach: Running barefoot reduces stresses on your feet and may prevent injuries known to afflict traditionally shod runners, a new study says.

In his bestselling book Born to Run, Christopher McDougal revealed that the best long-distance runners on the planet may be Mexico's Tarahumara Indians, who race barefoot or in thin sandals through the remote Copper Canyons of Chihuahua state.

The new study used high-speed video and a bathroom scale-like device called a force plate to digitally dissect the moment-by-moment stresses on the feet of 63 runners as they ran barefoot.

The research revealed that running barefoot changes the way a person's feet hit the ground.

Runners in shoes tend to land on their heels, so sports shoe makers have spent years designing footwear with gels, foams, or air pockets in the heels to reduce the shock of impact.

But barefoot runners more often land on the forefoot, near the base of the toes. This causes a smaller part of the foot to come to a sudden stop when the foot first lands, allowing the natural spring-like motion of the foot and leg to absorb any further shock.

"This form of landing causes almost no collision force," lead author Daniel Lieberman, an evolutionary biologist at Harvard University, said in an email.

Not that the benefits of barefoot running should be a surprise, he added: "Humans were able to run for millions of years without shoes or in just sandals."

The work, published online today by the journal Nature, is "really interesting and useful," according to coach, exercise physiologist, and author Jack Daniels.

"There is no doubt impact is a major source of injury," Daniels said via email, and reducing injuries is a key goal of all runners and coaches.

Daniels himself has done much of his own running barefoot.

"I eventually got to where I could go barefooted for five miles [eight kilometers] on a concrete sidewalk," he said, though he admits he prefers grass and well-cushioned tracks.

Even the latter, he added, takes practice.

"One main problem is the abrasion factor," he said. "You have to toughen up the skin on the bottom of your feet."

Luckily the choice won't be between shoes or no shoes for long. Shoe companies have been scrambling to design "minimalist" footwear that still protects the feet from rocks, thorns, and broken glass while allowing people to run more naturally.

"If you start with a thick shoe and slowly whittle down, at what point does the person start to run like they're barefoot?" pondered Sean Murphy, manager of advanced products engineering and sports research for shoe maker New Balance.

"We've completed those studies and come up with some pretty solid lines of thinking on how you make the foot work as naturally as possible and at the same time protect [it] from the elements," Murphy said.

"I'm pretty confident you're gong to see more and more products in that vein."